#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include <limits.h>
#include <stack>
#include <queue>
#include <map>
#include <set>
#include <algorithm>
#include <string>
#include <functional>
#include <vector>
#include <numeric>
#include <deque>
#include <utility>
#include <bitset>
#include <iostream>
using namespace std;
typedef long long lint;
typedef long double llf;
typedef pair<int, int> pi;
const int mod = 1e9 + 7;
int che[1000005];
int moebius[1000005];
int n, a[10005], b[10005], rng[10005];
lint cnt[1000005];
lint mod_inv(int x, int p){
lint ret = 1, piv = x;
while(p){
if(p&1) ret *= piv;
piv *= piv;
ret %= mod;
piv %= mod;
p >>= 1;
}
return ret;
}
int maxp;
void get_moebius(){
for(int i=2; i<=maxp; i++){
for(int j=i; j<=maxp; j+=i){
if(!che[j]) che[j] = i;
}
}
for(int i=1; i<=maxp; i++){
int cnt = 0, lst = -1;
int x = i;
while(x > 1){
if(lst == che[x]){
cnt = -1;
break;
}
lst = che[x];
x /= lst;
cnt++;
}
if(cnt < 0) continue;
moebius[i] = cnt % 2 ? -1 : 1;
}
}
vector<int> change[1000005];
int main(){
scanf("%d",&n);
for(int i=0; i<n; i++){
scanf("%d %d",&a[i], &b[i]);
}
maxp = *min_element(b, b+n);
get_moebius();
lint curr = 1;
for(int i=0; i<n; i++){
rng[i] = b[i] - a[i] + 1;
curr *= rng[i];
curr %= mod;
change[1].push_back(i);
}
for(int i=1; i<=maxp; i++){
for(auto &j : change[i]){
curr *= mod_inv(rng[j], mod - 2);
curr %= mod;
rng[j] = b[j] / i - (a[j] - 1) / i;
curr *= rng[j];
curr %= mod;
int s = i+1, e = maxp+1;
while(s != e){
int m = (s+e)/2;
if(b[j] / m - (a[j] - 1) / m != rng[j]){
e = m;
}
else s = m+1;
}
change[s].push_back(j);
}
cnt[i] = curr;
}
lint ret = 0;
for(int i=1; i<=maxp; i++){
for(int j=1; i*j<=maxp; j++){
ret += 1ll * i * moebius[j] * cnt[i * j] % mod;
ret %= mod;
}
}
printf("%lld",ret);
}
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
4 ms |
40900 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Halted |
0 ms |
0 KB |
- |
